After speaking with the island's director of operations, CNET was told Hangar 3 is being leased by a company called By & Large LLC. The tech news website was given a name and number for the company's point of contact, and when CNET tried calling the number they were greeted with a message saying "Thank you for calling Google. The number you dialed is no longer in service."

CNET then looked up the person, whose name is Tim Brandon, and his LinkedIn profile said Google was his client and that his responsibilities were to "lead and manage all acquisition and disposition activity for Google's Silicon Valley portfolio." But after CNET reached out to Brandon all mentions of Google were removed from his profile.

Locals also have heard that Google is behind the project, CNET said.

The tech website believes the project could be a floating data center, and that's because Google was granted a patent for exactly that back in 2009. That patent received a lot of hype at the time, but until now, nothing has really happened with it.

CBS San Francisco also reported that Google was behind the project, but said the structure was actually a floating retail store.

The CBS report describes the building as a "kind of giant Apple Store" for Google Glass, the company's wearable smartglasses. Once the project is finished, Google would tow the store to San Francisco's Fort Mason where it would open to the public, according to the report.

That possibility isn't too far-fetched considering there have been other reports recently that say Google is planning retail stores to show off Google Glass to consumers.